Scattering-type liquid crystal light valves have been quite mature in the last decade or so, which are mainly used in polymer-dispersed liquid crystals (PDLC). PDLE consists of a mixture of polymers and liquid crystals, and the polymers and the liquid crystals are made using a phase separation method. In most cases of the phase separation method, phase separation of the mixture material occurs by emitting an ultraviolet light or by a thermal process, such that the scattering-type liquid crystal light valves are in a scattering state under no applied voltage. In addition, switching between the scattering state and a light-transmitting state can be achieved by applying a voltage, and an applied voltage is needed to apply in this type of scattering-type liquid crystal light valve so as to fix the light-transmitting state of the light valve.
If a negative-type liquid crystal material (such as, a negative-type cholesteric liquid crystal material) is doped with salt-type ionic material, the degree of consistency or disorder of a cholesteric liquid crystal alignment can be directly controlled by a high voltage or a low voltage without having to unscrew a structure of the cholesteric liquid crystal alignment, such that the cholesteric liquid crystal is switched to a light-transmitting planar structure or a scattering focal conic structure and retains its bistable properties. Compared with PDLC, the cholesteric liquid crystal has a relatively fast switching speed (about several hundred microseconds), a relative small applied voltage, and a relatively high contrast. Further, the cholesteric liquid crystal has a quite good tolerance of materials and surface treatment.
As a result, researchers began to try to apply the above technology to smart windows. By applying different voltages to the cholesteric liquid crystal to form the light-transmitting planar structure or the scattering focal conic structure, the smart windows can have an effect of light transmission (corresponding to the planar structure) or an opaque effect (corresponding to the focal conic structure). However, at present, no researchers have developed suitable fabricating methods to commercialize the smart windows.
As a result, it is necessary to provide a method for fabricating micro-cell structures to solve the problems existing in the conventional technologies as described above.